In well-known methods, a yarn, especially a synthetic yarn spun from a melt spinning apparatus, is wound around a bobbin at a high speed by utilizing a winding apparatus such as that described in Japanese Laid-open Publication No. 5219/72 or in Japanese Laid-open Publication No. 60745/76.
In the winding apparatus described in Japanese Laid-open Publication No. 5219/72, when the amount of yarn wound around the bobbin reaches a predetermined quantity, the yarn running toward the full bobbin is cut by way of a yarn cutting device which is manually operated or which is mounted on a mechanically-operated doffing apparatus. Furthermore, the cut yarn end is sucked by a sucking device which is manually operated or which is mounted on the mechanically-operated doffing apparatus. Then the full bobbin is brought to a standstill after a high degree of deceleration. Thereafter, the full bobbin is doffed from the winding apparatus by way of the doffing apparatus. After a new empty bobbin is held by the winding apparatus, the sucked yarn is threaded onto the empty bobbin by hand or by way of the doffing apparatus. Thereafter, the threaded yarn is wound around the empty bobbin.
In the winding apparatus described in Japanese Laid-open Publication No. 60745/76, when the amount of yarn wound around the bobbin reaches a predetermined quantity, a turret for rotatably holding the bobbins is turned, the full bobbin is automatically replaced by an empty bobbin, the running yarn is automatically caught in a peripheral groove formed on the bobbin surface, and the yarn extending between the full bobbin and the empty bobbin is broken by the increased yarn tension. As a result, the yarn is successively wound around a bobbin without causing any stoppage thereof, and the full bobbin is doffed by way of a doffing apparatus.
In both cases, after a full bobbin is obtained, the full bobbin is doffed from the winding apparatus to a bobbin receiving apparatus of the doffing apparatus, which is of a type described in Japanese Patent Publication No. 11490/75, by way of a bobbin push-out device which is of a type described in Japanese Laid-open Publication No. 42867/76.
Since it is necessary to wind a regular-quality yarn around a bobbin during the whole winding operation, the yarn is advanced at a constant high speed and then wound around a bobbin at a high rotating speed, when a running yarn is cut after completion of package winding (in the winding apparatus described in Japanese Laid-open Publication No. 5219/72) or when a full bobbin is replaced by an empty bobbin after completion of a package winding (in the winding apparatus described in Japanese Laid-open Publication No. 60745/76). As a result, when the running yarn is cut, a yarn end extending from a full bobbin is rotated outwardly due to the centrifugal force created by the rotation of the full bobbin, and then the yarn is unwound from the full bobbin. Furthermore, in a winding apparatus, especially in a winding apparatus described in Japanese Laid-open Publication No. 5219/72, the full bobbin is decelerated rapidly, after the yarn running toward the full bobbin is cut and sucked by a sucking device, for decreasing the time required to replace the full bobbin with an empty bobbin and to restart the yarn winding around the empty bobbin, and for decreasing the amount of waste yarn sucked into the sucking device. Due to the reaction force of the above-mentioned rapid deceleration of the full bobbin, the yarn end is exposed to a tremendous force which causes the full bobbin to unwind. Accordingly, a long yarn end extends and hangs down from the full bobbin when the full bobbin is stopped. The length of yarn end may vary in accordance with the prevailing winding factors such as the quality and quantity of the oiling agent applied to the yarn, the winding speed of or the air flow around the winding apparatus. Sometimes, the yarn length may be equal to or more than 2M.
The above-mentioned long yarn end hanging down from the full bobbin causes various problems as described hereinafter.
The yarn end may entangle complicatedly around members of a doffing apparatus, such as a yarn cutting device or a yarn threading-up device. Accordingly, members mounted on the doffing apparatus may be damaged and cause problems in the operations of the doffing apparatus.
A transfer tail wind is usually formed on a bobbin at a position adjacent to a normally wound yarn package for facilitating the tail transfer operation in the succeeding yarn treating process. The above-mentioned yarn end may damage the transfer tail and decrease the commercial value of the yarn package.
While the doffed full bobbin, which is mounted on a package truck, is being transferred to a succeeding yarn treating process, such as a yarn-drawing process or a yarn package packing process, the yarn end may entangle around a transferring apparatus or around an apparatus situated at a position adjacent to the transferring path of the yarn package. In such cases, the apparatus and the yarn package may be damaged.
In addition, the yarn end may disturb the creel operation or the packing operation of the yarn package in the succeeding process, or the yarn end may often entangle around the creel apparatus or the packing apparatus.
However, no method for preventing the occurrence of yarn end hanging down from the full bobbin has been discovered yet.